Follow the lead ! Tracing the lead sources of Notre-Dame de Paris over the centuries using chemical and isotopic analyses

In this work, the challenges and progression in stable isotope investigation, from the analytical tools and technical sample preparation procedures to the dendroclimatological experiments, were reviewed in terms of their use to assess tree physiological responses to environmental changes. Since the isotope signature of whole wood is not always a reliable tool in studying the climate changes, cellulose is often preferred as the study material in paleoclimatic studies. Nevertheless, the isotope analysis of cellulose is challenging due to the difficulty to remove the other wood components (extractives, lignin, pectin, and hemicelluloses). Additionally, in the case of hydrogen isotope analysis, about 30% of the hydrogen atoms of cellulose are exchanged with the surrounding water, which complicates the isotope analysis. In recent years, more automated isotope analysis methods were developed based on high temperature pyrolysis of cellulose, followed by the chromatographic separation of H2 from CO and by their individual isotope analysis using isotope ratio mass spectrometry. When used to investigate climate factors, the combined isotope analysis δ13C and δ18O appears to be the most promising isotope tool. In contrast, the role of δ2H values is yet to be elucidated, together with the development of new methods for hydrogen isotope analysis.

Evolution of Ground Water Quality and Source Tracking of Nitrate Contamination in the Seymour Aquifer of Texas

Remembering the Dead in the Ancient Near East: Recent Contributions from Bioarchaeology and Mortuary Archaeology

The isotopic and impurity content of 15 water triple-point cells, manufactured at NMi VSL in the past three years, were investigated. The isotopic analyses were performed on water specimens sampled at three different stages of the manufacturing process. This allowed us to separate and quantify the influence of the source water and of the manufacturing process (distillation, degassing) on the final isotopic composition of the water in the cells. Inductively coupled plasma mass spectrometry (ICPMS) was conducted on selected water samples to investigate the potential contamination of the source water during the manufacturing process, and to evaluate the impact of impurities on the water triple-point temperature. The temperature differences among the manufactured cells were measured, and correlations between the observed differences and the results of isotope and chemical analysis were studied.

Karst springs are one of the most exploited drinking water resources in the world. Isotopic and chemical analyses on these waters reveal essential insights into their hydrodynamics. Valseriana (Northern Italy) is a valley within the Italian Pre-Alps, characterized by high water availability. The main reasons are a bedrock consisting of very permeable carbonate formations and a mean annual precipitation above 1800 mm/y. In this context, the Valseriana spring catchments have become strategically important for the water exploitation and the domestic supply of Bergamo and the neighboring municipalities. This study general aim is to expand the knowledge on the two main karst systems (Nossana and Ponte del Costone), which together include twenty-three major and minor springs, by defining a state-of-the-art that will be useful in future decades to preserve this crucial resource. Specific objectives include i) verifying the applicability of the 3H/3He dating method in karst environments, ii) defining groups of springs according to their chemical and isotopic characteristics for possible safeguard actions, and iii) establishing a conceptual model of the internal dynamics of the two spring systems. A chemical and isotopic sampling campaign was specifically conducted between May 2018 and July 2019. A total of 34 water points were sampled, including natural springs, rivers, wells, karst caves, and nearby mines. Water sampling for 3H/3He isotopic analyses was proved possible through careful selection of the sampling points and the insertion of the pump tubing in the spring fractures. A first classification of springs into uniform hydrochemical groups was obtained by applying the hierarchical cluster analysis technique on major ions contents. These outputs were combined with information from the 3H/3He dating analyses and resulted in three different classes of springs. The three classes showed a clustering for elevations: at high, medium, and valley bottom elevations, respectively. Finally, the elaborations simplified the two karst systems by a hierarchical flow system model, dynamically controlled by different karst network development and infiltration water.

The application of isotope and chemical analyses in managing transboundary groundwater resources

Isotope analysis was present at the birth of mass spectrometry and has since found application in a diverse array of fields including biology, medicine, archaeology, geology, chronology, forensics and environmental science. Quadrupole mass spectrometry (QMS) revolutionised chemical analysis by obviating bulky magnets, thus enabling truly portable chemical sensors. The central focus of this thesis is to investigate the marriage of the two: application of quadrupoles to isotope analysis, This work takes a specific interest in the isotopes “carbon-13” (13C) and “carbon-14” (14C) because of their applicability to archaeology, a motivating factor behind the thesis. In the case of the trace abundance 14C, notable for its application to radiocarbon dating, a novel approach is explored in which the aim is to quantify the contribution of this species by analysing isotopologues of carbon dioxide. Such an approach requires a step change in portable QMS resolution without cost to transmission rates. Factors in this objective are investigated by simulation of both two-dimensional (2D) and three-dimensional (3D) QMF fields. A well-known formula for minimum achievable peak width (Δm) is revised through re-analysis of the empirical data, and evidence for the practical mass-dependence of minimum Δm is presented. The fundamental relevance of the ratio of the inscribed radius (r_0) to the source aperture radius (r_ie) to high-resolution aspirations is examined using a new simulation tool allowing rapid visual 2D analysis of multiple ion trajectories. Through combination with other known resolution-enhancing parameters, the theoretical possibility of extreme resolutions of the order of 10^4 and 10^5 is demonstrated; some aspects are tested experimentally. For 13C analysis, a key concern is measurement stability, such that instrumental error does not exceed analytical requirements. This is a fundamental requirement for all isotopic analysis, and so occupies most of the experimental work presented in this thesis. Experiments are presented investigating significant factors leading to improved measurement stability in portable QMS including single, dual and triple filter systems, having hyperbolic and circular profile electrodes. The work is conducted with specific attention to the δ^13 C figure, a relative measure of the 13C/12C ratio; a threshold of ≤±1‰ precision (1σ standard deviation) is set for useful application to archaeology. This threshold is exceeded for two of the four experimental setups. Optimisation of the transmission efficiency of the quadrupole mass filter (QMF) can not only extend resolution limits, but also improve measurement stability by maximising ion current at the detector. The QMF transmission efficiency is not constant in a given instrument, varying according to m/z. The nature of this variation is, in turn, strongly influenced by the gap from ion source to QMF electrodes (source gap). A series of simulations and experiments are presented which (a) confirm the high fidelity of the 3D simulation model, (b) characterise the transmission of a QMF according to m/z and (c) demonstrate how the source gap may be optimised to maximise transmission efficiency. Portable QMS shows strong potential for applicability to carbon isotope analysis. Trace radiocarbon analysis through CO2 isotopologues is a theoretical prospect which awaits advancements in areas including precision voltage control and ion guiding at the micro-level. Stable carbon isotope analysis is found to be a real and present possibility which only awaits further experimental optimisation and the development of a robust experimental protocol for in-situ application.

H–O–C–S isotope and geochemical assessment of the geothermal area of Central Greece

In the current context of climate change, rock glaciers represent potentially important water resources due to the melting of ice they contain and/or their role as high mountain water reservoirs. However, the hydrology of these high-altitude debris accumulations is poorly known. Understanding the origin and quality of rock glacier outflows is essential to evaluate their contribution and impact on headwater systems. In this study, we developed a conceptual model explaining the main hydro-chemical processes in active rock glaciers in the current context of permafrost warming. This conceptual model was derived from isotopic and physico-chemical analyses performed on six rock glacier outflows in the Swiss Alps during the warm season. Similar chemical and isotopic analyses were performed in sources not fed by rock glaciers at all study sites. The ion content (SO42-, Ca2+, Mg2+ and NO3−) of the water emerging from active rock glaciers was globally higher than that of sources not fed by rock glaciers. Besides, the electrical conductivity and the ion content (SO42-, Ca2+ and Mg2+) of the active rock glacier springs increased during the warm season, tracking the increasing perennial ground ice melting. We hypothesized that the ionic fingerprint of melting ice points mainly to the remobilization of chemical compounds stored during a colder period of the past in the cryosphere (e.g., the 1960s–1980s).

<p>While the knowledge of the dynamics and internal structure of rock glaciers is well developed, a lack of understanding of their hydrological functioning is observed in the scientific literature. In particular, the origin and the quality of the water emerging from rock glaciers are not well known, together with its contribution to aquatic systems. Since rock glaciers are becoming increasingly important water sources under the influence of climate change, it is essential to improve knowledge about the modification of the hydrological regime of these high altitude debris accumulation, in particular by tracing ice melt in rock glacier outflows, and to quantify the impact of ground ice melting on the hydrochemistry of Alpine water systems. In this research, we combined isotopic and physico-chemical analyses for six rock glacier outflows in the Swiss Alps during the 2020 summer season. Chemical and isotopic analyses were also performed in sources not fed by rock glaciers at all study sites. The ionic content (SO<sub>4</sub><sup>2-</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, NO<sub>3</sub><sup>-</sup>) measured in water emerging from active rock glaciers and ice-patches was higher than that detected in sources not fed by rock glaciers. Water emerging from active rock glaciers and ice-patches was also characterized by an increase in electrical conductivity and in ionic content (SO<sub>4</sub><sup>2-</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>), and by isotopic (δ<sup>18</sup>O) enrichment during the warm season. The seasonal evolution of these physico-chemical and isotopic parameters could indicate the water supply related to ground ice melting in water emerging from active rock glaciers and ice-patches. We assume that the cryosphere stored atmospheric pollutants and other chemical elements during a colder period in the recent past (1960s-1980s) and that the current melting of rock glacier ice releases these chemical compounds in the Alpine water systems. The hydro-chemical processes taking place in active rock glaciers were summarized in a conceptual model based on the results of this study.</p>

Isotopic and molecular analysis on human, fauna and pottery remains can provide valuable new insights into the diets and subsistence practices of prehistoric populations. These are crucial to elucidate the resilience of social-ecological systems to cultural and environmental change. Bulk collagen carbon and nitrogen isotopic analysis of 82 human individuals from mid to late Holocene Brazilian archaeological sites (∼6,700 to ∼1,000 cal BP) reveal an adequate protein incorporation and, on the coast, the continuation in subsistence strategies based on the exploitation of aquatic resources despite the introduction of pottery and domesticated plant foods. These results are supported by carbon isotope analysis of single amino acid extracted from bone collagen. Chemical and isotopic analysis also shows that pottery technology was used to process marine foods and therefore assimilated into the existing subsistence strategy. Our multidisciplinary results demonstrate the resilient character of the coastal economy to cultural change during the late Holocene in southern Brazil.

Niutuozhen geothermal field is located in the Jizhong graben, belonging to the northern part of Bohai Bay Basin in North China. Chemical and isotopic analyses were carried out on 14 samples of the geothermal fluids discharged from Neogene Minghuazhen (Nm), Guantao (Ng), and Jixianian Wumishan (Jxw) formations. The δ2H and δ18O in water, δ13C in CH4, δ13C in CO2, and 3He/4He ratio in the gases were analyzed in combination with chemical analyses on the fluids in the Niutuozhen geothermal field. The chemical and isotopic compositions indicate a meteoric origin of the thermal waters. The reservoir temperatures estimated by chemical geothermometry are in the range between 60 and 108 °C. The results show that the gases are made up mainly by N2 (18.20–97.42 vol%), CH4 (0.02–60.95 vol%), and CO2 (0.17–25.14 vol%), with relatively high He composition (up to 0.52 vol%). The chemical and isotopic compositions of the gas samples suggest the meteoric origin of N2, predominant crustal origins of CH4, CO2, and He. The mantle-derived He contributions are calculated to be from 5 to 8% based on a crust–mantle binary mixing model. The deep temperatures in the Jxw reservoir were evaluated based on gas isotope geothermometry to be in the range from 141 to 165 °C. The mantle-derived heat fraction in the surface heat flow is estimated to be in the range of 48–51% based on 3He/4He ratios.

Water and gas geochemistry of the Euganean and Berician thermal district (Italy)

Optimisation of laser wavelength in the ablation sampling of glass materials

Chemical, crystallographic and stable isotopic properties of alunite and jarosite from acid—Hypersaline Australian lakes